Many religious people--including many or even most Modern Orthodox Jews--view the fact of evolution as compatible with religious tradition: Genesis is not to be taken literally, and God had a guiding Hand over the process of evolution.
Now, I like this take on religion and evolution, mostly because a) it's what I believed when I still believed, and b) it's good for honest religion and honest science. Indeed, some point to commentators like Ramban, who seems to suggest that God may have inserted a soul into a man-like animal to create humans. However, it is obvious that many religious people find evolution threatening, and it's important to ask why. Moreover, I have come to question the idea that religion and evolution can be squared so easily; it can be done, I'm sure, but I think it's harder than I used to assume. Here's a list of issues evolution presents for religion, some of which are culled from recent points I or others have made around the blogosphere. I'd be interested to see if anyone has any other points to add, or thinks these aren't such serious issues for the conciliatory point of view.
1. Evolution contradicts Genesis. An obvious starting point, yes, but even for those who say the Bible shouldn't be taken literally, one might wonder why God would write an account that looks like an actual description of creation to those who don't know better. I assume it was taken as literal by many people over a very long stretch of time, so how come only those of us living in the last 151 years get to understand that it is metaphorical? Is this not theologically confusing? ("God is mysterious and had a reason," I suppose. Post hoc and vague, but not unusually so. "People couldn't have handled it back then, so God waited until we were ready," I have also heard. I say: have you been to modern day Texas?)
Beyond this more minor point, though, some of the details become challenging. For example, Genesis discusses the creation of different animals, clearly stating that God created each animal "l'minah"--"according to its kind." From an evolutionary point of view, though, there is no such thing as a fixed, stable species with its own essence. Any two species can be connected via a series of intermediates in some pattern, with no sharp dividing line between them: any animal in the series was very similar to its parents and offspring. At a certain point, two groups of animals are different enough that they can no longer interbreed, and we call them two different species. So, the allegorical reader of Genesis must not only understand "God created" as "God guided the process of evolution," but also understand details such as "l'minah" as using "lashon b'nei adam" ("the common language of people"). Alternatively, the "creation" of a species involves the insertion of some essential soul into random animals in a series. (As noted above, IIRC, the Ramban actually suggests something along these lines about the creation of humanity--but that's what set humanity apart from animals. And, which animal should get the special essential soul of the species, if none had previously been essentially different from the prior or following links in the chain?)
To sum it up: evolution is not creation, and Genesis contains a creation story. It seems like it might need to be understood as a myth that contains a moral message in order to get off the ground, doesn't it? And at that point, aren't we wondering why God is writing a creation myth?
2. Let's suppose God has indeed providentially guided the process of evolution. Again, this gets harder when you examine the details. For hundreds of millions of years, animals have been competing, suffering, and dying. As may be obvious, animals can feel pain, so it is easy to begin to see "nature red in tooth and claw" when you consider evolutionary history. All that time and all that suffering was mandated by God to have a mechanistic process that would eventually churn out humans, in a tiny blip in the timeframe? The problem of evil becomes magnified a thousandfold.
3 & 4. As noted in the
last post I put up, Western religions assume humans have a special place in the universe. Evolution creates two problems for this. First, humans are a part of the same mechanistic process as all natural life, not on a special metaphysical plane--even though we still have unique abilities in the animal world. Second, at some point, presumably, a new species will branch out of
Homo Sapiens--making it a little harder for us to be the be all and end all. Once again, you have to assume the insertion of a special essence into humanity. Cognitive science has not been kind to the "ghost in the machine," though, making it an unnecessary entity that has been posited.
5. Evolution explains away the appearance of design in the universe, and as such, makes it unnecessary to posit that Someone was guiding the process (explored in more depth
here). Like the ghost in the machine in cognitive science, one is positing the unnecessary to explain the data.
Of course, it's certainly still possible to accept evolution and theology, and I hope many people continue to do so. However, it's interesting and worthwhile to consider why it is so threatening to so many religious people and how well it can actually be squared with religion. The above contains my first stab. Any thoughts?